There is a case in which the driver selects an appropriate traveling speed according to various road environments, but drives his or her vehicle at a speed exceeding a safe speed due to carelessness or the like. For example, patent reference 1 discloses a vehicle-mounted speed excess warning and informing device for calling the driver's attention to an excess in speed limit. This vehicle-mounted speed excess warning and informing device acquires information about the road speed limit on the road along which the vehicle is traveling from a center, and, when the current vehicle speed exceeds the speed limit, displays a warning on the display of the speedometer. Further, patent reference 2 discloses an auto-cruise control device for, when detecting a curve on a route to be traveled while a vehicle is traveling at an auto cruise setting speed, computing the highest vehicle speed that enables the vehicle to pass through the curve properly to reduce the speed of the vehicle to the highest vehicle speed. In addition, a vehicle control device described in patent reference 3 has a unit for recognizing two or more speed limits, and, only when these speed limits match each other, controlling a vehicle in such a way that the vehicle travels at a speed equal to or lower than the speed limits. Further, patent reference 4 discloses a vehicle-mounted device for providing a vehicle approaching a traffic light with information about a proper speed. This vehicle-mounted unit captures information about switching timing for traffic light control, and computes either a maximum traveling speed that enables the vehicle to stop before an intersection or a maximum traveling speed that enables the vehicle to enter an intersection by the time a yellow light ends at the intersection to present the maximum traveling speed to the driver.